Cars (and airplanes) are becoming more like computers. So I am predicting that their weakness will be in the electronics. You will be replacing PC boards before mechanical components, and, like computers, they will become obsolete faster.
Technology obsolescence in general isn't planned so much as accepted as the natural order of things. But I find it hard to understand your assertion that car electronics in particular increase the rate of obsolescence. I find quite the opposite to be the case,
I've never sold or scrapped a car because of a failed ECM, nor replaced an ECM / PCM, nor had any need to. In fact, in my entire lifetime, I've only replaced three components associated with any of my cars' computer systems: an 02 sensor, an EVAP vent solenoid, and a fuel tank pressure sensor.
On the other hand, I sold a 2001 Saturn SC1 last year because it needed a bunch of chassis and suspension work that I didn't feel like doing. I sold a 2000 Kia Sportage a few months before that for similar reasons. Both cars still ran well, however, and could be restored by people who had more time than I did for body, chassis, and suspension repairs.
Both of the cars' "computers," on the other hand, were fine. They had operated trouble-free for the cars' entire lifetimes and were still doing so when I sold the cars. How many desktop computers can boast similar records?
I remember and have owned cars from before the era of computerization that had carburetors, breaker points, coils, and so forth rather than today's computer-controlled systems. Those cars and components required far more maintenance, far more often than today's cars.
Spark plugs lasted about 10K miles back then, not 100K. They usually were changed as part of an annual "tune-up" that also included, at a bare minimum: cleaning, adjusting, or replacing the breaker points and condenser; cleaning, adjusting, or rebuilding the carburetor and choke; and adjusting the tach, dwell, and timing. Other frequently-needed maintenance included included adjusting the valves, replacing spark plug wires, and replacing the ignition coil.
Back then, warranties maxed out at 50,000 miles
at the very most. 36,000 miles was more common, and some manufacturers' warranties were as short as 10,000 miles. The warranties excluded all of the above maintenance chores. They were considered routine and necessary maintenance and were the owners' responsibility. Odometers only went up to 99,999 miles because it was unusual for cars to make it past 75,000 or thereabouts, much less 100,000.
And let's not forget fuel economy. The average fuel economy of a passenger car in 1960 was 14.3 MPG, and in 1970 was 13.5 MPG. Fuel economy didn't top 20 MPG until 1990, by which time the hated electronics had become standard on almost all cars.
Yet a lot of people consider the days of carburetors, breaker points, fuel guzzling, and engines that died by 75,000 miles the "good old days" and hate today's "computerized" cars that require little maintenance, come with 100,000 mile warranties, and frequently top 200,000 miles without fanfare. It's kind of baffling really.
For my part, I'm not going to complain much about car electronics. Neither do I think technology contributes to a car's obsolescence considering the extraordinary increase in their average lifespans. Most cars used to be ready for the junkyard by 75K.
Rich